The present invention relates generally to a method and apparatus for minimizing the emission of particulate-laden smoke to the ambient atmosphere prior to the final quenching of incandescent coke. More specifically, the present invention discloses a method and apparatus for suppressing combustion of incandescent coke upon its extrusion from a slot type oven and for avoiding the emission of that amount of particulate matter which otherwise would be drawn into the thermal updraft created by the incandescent coke.
The ever-increasing concern over environmental pollution has focused on a number of industrial operations that emit substantial amounts of gaseous and particulate materials to the ambient atmosphere. Various gas-cleaning devices have been employed to capture such emissions such as electrostatic precipitators, scrubbers, etc. However, such devices have generally been applicable for use only in conjunction with fixed or stationary collecting structures. Thus, there is a need for such systems that may be employed wherein vehicular operations are encountered, at least in part, and which require emission control.
One particular industrial operation producing substantial gaseous and particulate emissions is the movement of incandescent coke from a slot oven and the conveyance of such incandescent coke to a remotely located quenching station whereby the coke is cooled for subsequent use, for example in iron production. Typically, coke is pushed or extruded from any one of several individual oven chambers in a slot-type battery into a moveable guide by which the coke is constrained to fall into an open-top railroad vehicle while it is moving past a loading point adjacent to the coke oven. As the coke emerges from the oven, the gaseous and particulate emissions are relatively minor until the coke begins to break up as it leaves the coke guide to drop into the vehicle thereunderneath. This extruding and falling normally results in the generation of a substantial quantity of sooty smoke and other particulate matter of the type that pollutes the ambient air and atmosphere, and emissions may continue while the vehicle travels. Both the emission intensity and duration are expected to be greatest where the battery is older and in need of retrofit controls because the pyrolysis of coal to coke is more erratic in such production entities.
Thereafter, the filled vehicle is then moved to a quenching station located remotely from the coke oven wherein the coke deployed along the bottom of the vehicle is heavily sprayed with water to quench the same.
Although the prior art has considered various hood constructions for controlling coke emissions upon its extrusion into an open-topped vehicle, such prior art hoods simply cover the coke guide and underlying vehicle in an attempt to collect the thermal updraft and entrained emissions during breaking of the coke as it falls into the receiving car. However, temperatures developed during such extrusion of the coke are substantial which can lead to the structural failure of such collectors and their associated ducting to gas cleaners and consequently only result in a minimum control of pollutants passing to the atmosphere.
In addition, the prior art has attempted to construct, in effect, vehicular quenching stations communicating with the coke guide whereby the coke is either quenched immediately subsequent to its extrusion or is subjected to quenching operations during its conveyance away from the coke guide as by transitory quenching equipment assembled on a vehicle so as to move therewith. However, these prior art structures render useless the substantial number of open-topped vehicle quenching installations utilized in the industry which are remotely located from coke ovens.
It is in this regard of devising a method and apparatus for not only controlling coke emissions during its extrusion into an open-topped vehicle but also during conveyance of the coke in such a vehicle to remotely situated quenching stations that the present invention is considered most important. Those knowledgeable in coke-producing operations are aware of the fact that often times on older ovens portions of incompletely carbonized coal are pushed from a coke oven into an open-topped vehicle. This is known as a so-called "green push". Unlike completely carbonized coke, which generates particulate emissions only during the coke oven push and during the quenching, a "green push" will emit substantial emissions during the whole time interval for movement between the coke oven and quenching station. The method and apparatus of the instant invention controls emissions of a "green push" during the period of time when the coke is being extruded and subsequently until the coke is quenched, thus offering a substantial advantage over prior systems. Such control is accomplished without complex conveyance equipment as used in some prior art methods which are, in effect, vehicles specially designed for receiving, transporting, quenching and discharging incandescent or newly-quenched coke.